1. Field of the Invention
The present invention relates to a model generating method, a model generating program, and a simulation apparatus for generating a model of estimating the state of an object.
2. Description of the Related Art
If a physical model of an object can be obtained accurately, the object can be controlled at high precision by performing a required operation so as to be adapted to a purpose. In an actual object, however, various elements are related to each other complicatedly, so that it is often difficult to construct an accurate physical model. A technique of deriving a function indicative of input/output characteristics by using an exponential function approximation method based on measurement data obtained by measuring the input/output characteristics of the object is known (for example, Japanese Patent Application Laid-Open JP-A No. 2000-321174, claim 1 and paragraph number 0009).
A technique of preparing a physical model and adjusting parameters of the model so as to eliminate a difference between an output from the model and an output obtained from the actual object is also known (for example, JP-A No. 9-142280, FIG. 3).
In the technique described in JP-A No. 2000-321174, the input/output characteristics are approximated by a statistical method such as the exponential function approximate method. The measurement data is sampled discretely, so that the behavior of an object between a certain measurement point and the next measurement point is not reflected in the model. Therefore, it is difficult to construct an accurate model. The technique is inconvenient, for the number of measurement processes increases, when the number of measurement points is increased to improve precision of the model.
In the technique disclosed in JP-A No. 9-142280, it is necessary to adjust parameters of a physical model. In the case of modeling an object in which various elements are related to each other complicatedly, it is not easy to determine a control rule of the parameters, that is, to determine which parameter should be changed and how much degree of the change. Even if the parameter control rule is obtained, to obtain an accurate physical model, it is necessary to measure a number of measurement points and execute an enormous amount of calculation. Therefore, the technique described in JP-A No. 9-142280 has problems such that it takes long time to obtain measurement data and a calculation load is heavy.